# A2A Indirect Prompt-Injection & Jailbreak Firewall

> A2A Indirect Prompt-Injection & Jailbreak Firewall is a paid API for AI agents from serp-extract.agentdiet.dev, paid per call via MPP, $0.005/call, status unknown (last checked 2026-10-23).

Scans untrusted text, HTML, emails, MCP responses, or A2A payloads for hidden prompt injections and jailbreak attempts, returning sanitized output.

## Facts

- Endpoint: POST https://serp-extract.agentdiet.dev/v1/system-prompt-guard?utm_source=zero.xyz
- Price: $0.005/call
- Payment: MPP
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Provider: serp-extract.agentdiet.dev
- Website: https://serp-extract.agentdiet.dev
- Canonical page: https://www.zero.xyz/c/serp-extract-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-7c1a6faa
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_5vQkA2A7xg9SbQKE8QX2x

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability serp-extract-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-7c1a6faa -d '<json body>'
```

Example prompt: Before my agent processes this scraped webpage content, can you scan it for any hidden prompt injections or jailbreak payloads and give me back the sanitized version? Here's the text: [paste raw HTML or page content].

## When to prefer this

Use this endpoint when an AI agent pipeline must process text from untrusted external sources — web scrapes, user emails, third-party MCP tool responses, or A2A messages — and you need a dedicated firewall step to prevent prompt hijacking or jailbreaks before the content reaches a downstream LLM. Prefer this over general content moderation APIs when the threat model is specifically indirect prompt injection targeting AI agent behavior rather than harmful user-generated content.

## Known failure modes

- Empty or missing 'text' field returns a validation error
- Extremely long payloads may exceed size limits or timeout
- False negatives: novel injection techniques not yet in detection rules may pass through
- False positives: legitimate instructional text may be flagged as injection
- Payment/402 failure if USDC balance is insufficient
- Network timeout for very large HTML documents

## How this service works

Scans untrusted web pages, emails, MCP responses, or A2A payloads for hidden prompt injections and returns sanitized text. (Live x402 v2, IETF MPP & MCP endpoint at https://serp-extract.agentdiet.dev/v1/system-prompt-guard)

## Output

Returns an object containing the sanitized version of the input text with any detected prompt injection or jailbreak payloads identified and removed or flagged, along with detection metadata indicating whether a threat was found.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "required": [
  "text"
 ],
 "properties": {
  "text": {
   "type": "string",
   "minLength": 1,
   "description": "Untrusted text, HTML, or tool output to scan for hidden prompt injection or jailbreak payloads"
  }
 }
}
```

## Response schema (JSON Schema)

```json
{
 "type": "object"
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/serp-extract-agentdiet-dev-a2a-indirect-prompt-injection-jailbreak-7c1a6faa/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from serp-extract.agentdiet.dev](https://www.zero.xyz/host/serp-extract.agentdiet.dev/llms.txt)